The invention pertains to the field of valves and nozzles for the dispensing of viscous materials and, in particular, to the dispensing of viscous materials from cartridges typically used in caulking guns. While particularly suited to the dispensing of very viscous and difficult to dispense materials, the new valve and nozzle combination is not limited thereto but is suitable for dispensing a wide variety of materials not necessarily of high viscosity.
The typical cartridge type of dispenser for caulking, sealant or glue comprises a cardboard tube with one metal end sealingly attached to the cardboard tube. A plastic nozzle, snout or applicator tip extends from the metal end. As manufactured and sold the applicator tip is sealed. An additional internal aluminized plastic seal covers the opening through the metal end into the cartridge tip. The other end of the tube includes an internally mounted diaphragm seal or cover that is engageable by the caulking gun plunger to apply pressure to the material in the tube and thereby expel the material through the applicator tip.
Before applying pressure to the diaphragm, the tapered end of the applicator tip is opened and trimmed by the user to provide the desired opening diameter and a nail or other sharp pointed object is inserted to pierce the aluminized plastic seal.
Unfortunately, once the cartridge is opened, the applicator tip or nozzle can not be properly closed or resealed in a manner that prevents air from entering and causing the material in the applicator tip to harden. Since the applicator tip is tapered, the slug of hardened material becomes difficult to expel. Typically, increased force applied to the plunger causes the cardboard to burst with the result that the material can no longer be properly dispensed from the cartridge.
A cap to cover the trimmed applicator tip can be applied as provided with some cartridges, however, the cap is removed during use and can easily be mislaid. The separable cap also permits air to be trapped at the tip thereby permitting hardening of material at the tip to ensue.
Valves such as that disclosed in U.S. Pat. No. 2,859,932 can be used to control the passage of liquids. Such valves provide a tortuous path for a liquid or a somewhat viscous material. Where the viscous material is very viscous, the tortuous path can greatly impede the flow of the material. Secondly, such a valve does not provide a straight through path and therefore if applied as a factory installed permanent part of the cartridge, the aluminized plastic seal cannot be utilized because a nail can not be put through the valve to break the seal.
With a view toward overcoming the problems noted above, the applicant has developed the valve disclosed and described below.